幻方
幻方是一個方陣,其階數為奇數,每行、每列和每條對角線的元素之和都相同。
每行、每列或每條對角線的總和可以使用此公式計算:n(n²+1)/2
以下是構造幻方的規則:
- 我們將從矩陣第一行的中間列開始,並始終移動到左上角放置下一個數字。
- 如果行超出範圍或行不在矩陣中,則將列更改為最左列,並將數字放在矩陣的最後一行,然後再次移動到左上角。
- 如果列超出範圍或列不在矩陣中,則將行更改為最頂行,並將數字放在該矩陣的最後一列,然後再次移動到左上角。
- 當左上角不為空或行和列都超出範圍時,則將數字放在最後放置數字的底部。
輸入和輸出
Input: The order of the matrix 5 Output: 15 8 1 24 17 16 14 7 5 23 22 20 13 6 4 3 21 19 12 10 9 2 25 18 11
演算法
createSquare(mat, r, c)
輸入:矩陣。
輸出:行和列。
Begin count := 1 fill all elements in mat to 0 range := r * c i := 0 j := c/2 mat[i, j] := count //center of top row while count < range, do increase count by 1 if both i and j crosses the matrix range, then increase i by 1 else if only i crosses the matrix range, then i := c – 1 decrease j by 1 else if only j crosses the matrix range, then j := c – 1 decrease i by 1 else if i and j are in the matrix and element in (i, j) ≠ 0, then increase i by 1 else decrease i and j by 1 mat[i, j] := count done display the matrix mat End
示例
#include<iostream> #include<iomanip> using namespace std; void createSquare(int **array, int r, int c) { int i, j, count = 1, range; for(i = 0; i<r; i++) for(j = 0; j<c; j++) array[i][j] = 0; //initialize all elements with 0 range = r*c; i = 0; j = c/2; array[i][j] = count; while(count < range) { count++; if((i-1) < 0 && (j-1) < 0) //when both row and column crosses the range i++; else if((i-1) <0) { //when only row crosses range, set i to last row, and decrease j i = r-1; j--; }else if((j-1) < 0) { //when only col crosses range, set j to last column, and decrease i j = c-1; i--; }else if(array[i-1][j-1] != 0) //when diagonal element is not empty, go to next row i++; else{ i--; j--; } array[i][j] = count; } // Printing the square for(i = 0; i<r; i++) { for(j = 0; j<c; j++) cout <<setw(3) << array[i][j]; cout << endl; } } main() { int** matrix; int row, col; cout << "Enter the order(odd) of square matrix :"; cin >> row; col = row; matrix = new int*[row]; for(int i = 0; i<row; i++) { matrix[i] = new int[col]; } createSquare(matrix, row, col); }
輸出
Enter the order(odd) of square matrix :5 15 8 1 24 17 16 14 7 5 23 22 20 13 6 4 3 21 19 12 10 9 2 25 18 11
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